1. Field of the Invention
The present invention relates to a data processing apparatus comprising a processing unit for fixed-length data processing and a processing unit for variable-length data processing.
2. Description of the Related Art
Most conventional CPUs are based on fixed-length data processing. Therefore, fixed-length data is processed by such a CPU, and various peripheral units are controlled by fixed-length data.
In such processing performed by fixed-length data, however, since calculation and transfer are executed by data having a fixed number of bytes, unnecessary digits must be processed. For this reason, a processing speed is low, and an operation efficiency of a memory used in the processing is reduced.
Therefore, a system is conventionally proposed to use a CPU capable of processing variable-length data by a software-like means using programs, thereby increasing the processing speed and memory efficiency. If variable-length data is processed by such a means, however, a load applied on the software is undesirably increased very much.
In the conventional apparatuses, therefore, when only fixed-length data is used, a processing speed is lowered, and an operation efficiency of a memory used in processing is reduced. If a CPU capable of processing variable-length data by a software-like means using programs is used, a load applied on the software is increased.